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MG MGB Technical - Front Suspension Resuild Results

Just wante to document the results of my front suspension rebuild. As background, I just bought a 72 mgb roadster. Needed to replace coil spring and all bushings in fron end. There was several recommended good methods. I am not very mechanically inclined and was a little reluctant for this undertaking. I got everything apart in 1 weekend, here's my learnings.
1. Crack loose the wheel holding hubs.
Jack car up putting trolley jack under from major mount under the from he engine.
2. Put jack stands on each side on the ribs under the body frame.
Now it's best to just disconnect disk brake caliper. Undue the hard tube connection, then disconnect the hose connection from mount and put this on a shelf. Re-bleeding the brakes is easier than having this is your way.
3. Remove trolley jack and replace it under the king pin mount and jack the swivel axel assembly just until the shock arms lift off their bumpers about 10mm.
4. Then I removed all the cotter pins and sprayed all the bolts/nuts with a penetrating rust buster.
5. Next, I broke loose the upper trunnion pin attaching shock arm to swivel axel assembly. While everything still together, I tried to get all bolts/nuts broke loose.
6. I took a cargo strap and tied to coil spring to the down pipe just incase it got loose it couldn't fly out and hurt me.
Now you need to take the bolt out from the steering rack to the swivel axel. Again, penetrating oil and lot's of wacks with a hammer. After 10-20 wacks, it all a sudden pops out. This is a tappered fit evidently and was the hardest to get out. Don't be afraid to wack hard and again, leave nut on just off the end so you wacking the nut and actually not the end of the bolt. This prevents mushrooming bolt threads. If you have a sway bar, disconnect end links.
7. Now it was time to undue the top trunnion bolt and get it out. The nut cam unloose fine, then I left it screwed on just past the end to wack it with a hammer and get the trunn ion bolt slidding out the other side. One I got the bolt moving, I then removed the nut and took a 1/4" rachet extension and wacked it the rest of the way out. Don't be afraid to hit it hard and re-apply penetrating oil if necessary.
8. Once the top trunnion bolt is out, now your ready to lower the jack slowly and the botton spring pan and whole assembly will lower. I put a piece of carpet under, becasue swivel axel assebly will swilvel and fall to the floor. Slowly lower the jack and the tension will relieve from the spring.

Everything went just as described on this site. Only thing missing in instructions was disconnecting steering rack connection and making it clear that hard wacking is not unusual.

9. Once the swilvel axel and spring pan was lowered, I got spring out easily and then just started taking the lower outside trunnion bolt, the inner bolt connecting back side of spring pan and all the spring pan to wishbone bolts apart.
10. The bolts holding the spring pan to wishbone arms will probably break off, then just wack then out. If they don't break, use a metal cutting saw if you have too.
11. Now, clean and wire brush everything you can get to. Also, good time to check motion and oil level in shocks. If you push shocks upward, should be resistance and when you let go, they fall down slowly. Mine was not so much resistance, it was low on oil. I filled with 20 weight hydraullic oil and then they seemed fine.

If you clean well, you fine bolt heads, the real color of the shocks and can get the whole assembly looking nice and clean. I used degreaser, hand wire brush and wire brush on my drill. Then I wiped everything off and finally used break cleaner to get the final layer of oil off before painting everything nicely. The suggestion to use aluminum foil to wrap everything you don't want painted in close proximity worked well. On the inner side of corner panel, I cleaned any loose previously applied undercoat off. It was the tar type stuff. I then used a truck bed liner paint to refresh everything. Take care not to get paint on threads, shocks, bushing mounts, disc rotor, and grease fittings. I put new grease in king pin assembly before painting and covered the spring area. Aluminum foil, or stick paper towels in holes or to cover anything that should not receive paint.

Before I order parts, I have a few questions.

1. The first spring pan I got off looked a little bent. The second was same way. Looked like its designed this way with a little tilt to one corner?

2. The coil springs are rusty, but don't seem like they need replaced. On one side they only had 2 bolts holding spring pan and the spring had the inner side of the pan pushed down about 5-10 mm. They had some sort of wedge in spring to compensate. I am thinking now that I can replace all spring pan bolts, that the springs are ok. Just clean them up and paint them.
I measure the ht of the front end before taking apart. it was 24.5 - 25 inches. This seemed about normal to other threads on this site.

3. The swing arm was missing altogether. How important is this or was it only for cornering at high speed? I can order an V-8 upgrade I think is 5/8" or 3/4". Original of 9/16 is no longer available. This is about $75-$100 US. Is this needed right away or could wait and still be safe driving?

Thanks a bunch guys. Followed suggestions and it all worked.

Again, I dis-assembled both side in 1 weekend, including lots of cleaning and painting all ready to reassemble.

Best regards,
Doug
DT Toms

Doug,
You should measure the free height of the coil springs to determine if they need replacement. I don't remember the height for a 72 off the top of my head - I remember for my 68 the free height is 9.9".

When you refer to swing arm, do you mean sway bar? If so, I have an original size 9/16" sway bar - if you'd be interested in it email me and we can discuss. Thanks.

Jack
Jack Caulder

Jack,
Yes, I was talking about the anti-sway arm.
It was missing altogether.
I read that the earlier models didn't have this.
How important is it if your just a dialy driver?
Is it just for hard cornering or does it give you better feel and handling at regular speeds and road conditions?

Is the 9/16 just fine or does the V-8 upgrade to 5/8 give you better results? I'll e-mail you for details on your part. I need mounting brackets and link ends.

Best regards,
Doug
DT Toms

Doug- Good story, just what we need for the growing body of knowledge. I found the need to do the swivel axle rebuild on my 71 as the slop was extensive. I had converted to tube shocks a couple years previous and switched back to the rebuilt stock dampers at that time and was satisfied. I think either sway, 9/16 or 5/8 will show improvement in front end reaction for you. Carry on. Vic
vem myers

Doug,
I thought all MGB's had a front sway bar, but the earlier (chrome bumpered?) models didn't have a rear sway bar. The sway bar helps reduce body roll while cornering. It would be a matter of preference to what size is best. I wanted a little flatter cornering but not a significant harshness increase and went for a 5/8" sway bar instead of retaining the stock 9/16" bar.

Jack
Jack Caulder

Thanks all.
This result was a follow-up to a previous thread with many people here helping me through this work

I couldn't find the thread to put my results there.

I guess they get archived, but didn't see it.

I hope all that helped see these results.

Best regards,
Doug
DT Toms

DT: You will be perfectly safe without a front sway bar. Many MGBs do not have them. You car will handle acceptably but one day you may want to add a front bar to enhance handling. Just rebuilding the front end as you have done will make an enormous difference. Wait till you have the spare change to upgrade.
Terry

Here is a trick an old timer showed me to remove tierod end from the steering arm. Loosen the nut on the tie rod end - but don't hit it. Turn the hub so the steering arm faces out from under the guard. Use a large hammer and belt the end of the steering arm. The force should be directed along the steering arm.
Three or 4 good wacks and the tie rod springs loose.

The nut will protect the tie rod thread if you miss with the steering arm with the hammer. There will be no damage to the tie rod or the thread so you can reuse the tie rod without any concern.

BGT 77
Tahiti Blue
RM Taylor

This thread was discussed between 04/10/2004 and 05/10/2004

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.